Place the pork in the slow cooker. Season top of pork with salt, pepper, onion powder, and garlic powder. Pour beer into the bottom of the slow cooker and place the lid on the slow cooker crock.
Cook pork on High for 1 hour. Reduce slow cooker heat to Low and cook for at least 8 hours or overnight.
Remove pork from the slow cooker and shred with two forks. Discard juices and rinse out slow cooker crock. Return shredded pork to slow cooker and stir barbeque sauce into pork.
